Pneumatic tired wheels are widely used in virtually all types of land vehicles, including automobiles, trucks, trailers, tractors, other self propelled and unpowered vehicles and aircraft landing gear. The intense development activities involving pneumatic tired wheels and tires has resulted in a highly developed state of the art with respect to tire design, including the development of tubeless tires and so-called radial tires which allow substantial deflection of the tire sidewall during normal operation to improve vehicle handling performance, cushion the vehicle against road imperfections, improve vehicle operating efficiency and lengthen tire life through reduced friction due to tire deflection.
However, a substantial limitation on the performance of pneumatic or gas medium charged tires, is directly caused by the loss of inflation pressure. Various attempts have been made to eliminate loss of charge pressure due to tire wall puncture and provide tire designs which will enable the tire to continue to operate in a deflated or "run-flat" condition. Of course, conventional pneumatic tires, if deflated, cause substantial loss of vehicle control and tire and wheel damage quickly result from any attempt to operate the vehicle.
For example, efforts have been directed at developing tires with sidewall and tread reinforcements and wheel rim configurations which permit tires to operate in the run-flat condition. These efforts have only been partially successful and still result in reduced vehicle stability and control and undesirable changes in tractive effort due to changes in effective wheel diameter and tire deflection. Moreover, run-flat tires have been developed with a view to eliminating the need for a spare tire onboard the vehicle and the problems associated with changing deflated pneumatic tires under on-the-road conditions as well as the desire to eliminate the problems associated with the space required in the vehicle to stow a spare tire and the associated tire changing tools.
Accordingly, considering the problems associated with providing conventional spare tires and tools and the somewhat inadequate solutions provided by self-sealing and prior art run-flat tire designs, efforts also have been directed to providing vehicle wheels with run-flat support devices which may be installed within the wheel-tire pressure chamber or cavity and which support the tire in an under-deflated or run-flat condition.